N-Substituted imido-dicarboxylic acid diaryl ester method of preparation

ABSTRACT

Novel N-substituted imido-dicarboxylic acid diaryl ester compounds of the general formula ##STR1## in which R 1  represents an optionally substituted aliphatic, cycloaliphatic, araliphatic, aromatic, heterocyclic radical and 
     R 2  and R 3  can be identical or different and represent an optionally substituted aryl radical, 
     and a process for their preparation characterized in that a carbamic acid aryl ester of the general formula: 
     
         R.sup.1 --NH--CO--OR.sup.2                                 (II) 
    
     in which R 1  and R 2  have the abovementioned meanings, is reacted with a carbonic acid aryl ester halide of the general formula 
     
         X--CO--OR.sup.3                                            (III) 
    
     in which 
     R 3  has the abovementioned meaning and 
     X represents a halogen atom, optionally in the presence of a diluent, optionally at a temperature between 100° and 300° C. 
     The new compounds (I) can be used as intermediate products for the preparation of known herbicidal active compounds from the 1,3,5-triazine,2,4-(1H,3H)-dione series.

This is a continuation application of U.S. Ser. No. 350,057 pendingfiled Feb. 18, 1982, which in turn is a divisional of Ser. No. 233,248filed Feb. 10, 1981, now abandoned.

This invention relates to certain N-substituted imidodicarboxylic aciddiaryl ester compounds and to a process for their preparation. Inadditional aspects, the invention relates to the use of such compoundsas intermediate products, and processes, for the synthesis ofherbicides.

The invention provides, as new compounds, the N-substitutedimido-dicarboxylic acid diaryl ester compounds of the formula ##STR2##in which R¹ represents an optionally substituted aliphatic,cycloaliphatic, araliphatic, aromatic, heterocyclic radical and

R² and R³ can be identical or different and represent an optionallysubstituted aryl radical.

The present invention further provides a process for the production ofcompounds of the present invention characterised in that a carbamic acidaryl ester of the general formula

    R.sup.1 --NH--CO--OR.sup.2                                 (II)

in which R¹ and R² have the abovementioned meanings, is reacted with acarbonic acid aryl ester halide of the general formula

    X--CO--OR.sup.3                                            (III)

in which

R³ has the abovementioned meaning and

X represents a halogen atom, optionally in the presence of a diluent,optionally at a temperature between 100° and 300° C.

It is to be described as surprising that the reaction according to theinvention proceeds, since carbamic acid aryl esters do not react withcarbonic acid aryl ester halides in the desired manner in the presenceof an acid-binding agent: it is indeed known that N-substituted dialkylimido-esters can be prepared by reacting N-substituted carbamic acidalkyl esters with carbonic acid alkyl ester chlorides in the presence ofmetallic sodium (see J. Amer. Chem. Soc. 69, 2616-2618 (1947).

However, attempts to apply this method to the corresponding aryl estersfail completely. For example, neopentyl-carbamic acid phenyl esterreacts with carbonic acid phenyl ester chloride under the reactionconditions according to the state of the art to give exclusivelyneopentyl isocyanate and diphenyl carbonate. Even with butyl-lithium asthe acid-trapping agent, no neopentylimido-dicarboxylic acid diphenylester is formed. It is all the more surprising that the reactionaccording to the invention proceeds smoothly at elevated temperature andin the absence of an acid-trapping agent. According to the state of theart, it would have been expected that total re-splitting of the carbamicacid aryl ester employed into isocyanate and phenol would take place(see Houben-Weyl: Methoden der organischen Chemie (Methods of OrganicChemistry), 4th Edition. Volume 8, page 127 (1952)).

If neopentyl-carbamic acid phenyl ester and carbonic acid phenyl esterchloride are used as starting substances, the course of the reaction canbe represented by the following equation: ##STR3##

Preferred compounds of the present invention and starting substances offormula (I) are those in which R¹ represents a straight-chain orbranched alkyl radical which has 1 to 10 carbon atoms and is optionallysubstituted by lower alkoxy, lower alkylmercapto, halogen (in particularchlorine), cyano or nitro; an alkenyl radical with 3 to 8 carbon atoms;an alkinyl radical with 3 to 8 carbon atoms; a cycloaliphatic radicalwhich has 5 to 8 ring carbon atoms and can optionally be substituted bylower alkyl; an araliphatic radical with a total of 7 to 12 carbonatoms, it being possible for the aromatic ring system optionally to besubstituted by halogen, nitro, trifluoromethyl, cyano, lower alkyland/or lower alkoxy; an aromatic radical which has 6 to 12 carbon atomsand optionally substituted by halogen, nitro, trifluoromethyl, cyano,lower alkyl and/or lower alkoxy, or a heterocyclic radical with 5 or 6ring atoms, it being possible for 1 to 3 hetero-atoms, such as oxygen,sulphur and/or nitrogen, to be present in the ring system, R² representsa phenyl or naphthyl radical which is optionally substituted bychlorine, methyl and/or methoxy and, in the case of compounds of thepresent invention, R³ independently of R² has any of those meaningsgiven for R₂.

The expressions "lower alkyl", "lower alkoxy" and "lower alkylmercapto"in the contect of this invention are intended to denote appropriateradicals with in each case 1 to 4 carbon atoms.

The carbamic acid aryl esters of the formula (II) used in the process ofthe present invention are already known, or they can be prepared byknown processes, by addition of isocyanates onto phenols (seeHouben-Weyl, Methoden der organischen Chemie (Methods of OrganicChemistry), 4th Edition, Volume 8, page 142 (1952)) or by reaction ofcarbonic acid aryl ester chlorides with primary amines (see Houben-Weyl,Methoden der organischen Chemie (Methods of Organic Chemistry), 4thEdition, Volume 8, page 138 (1952)). The starting compounds of theformula (II) can furthermore be prepared by reacting carbonic aciddiaryl esters with amines (see Preparative Example 5b; see alsoHouben-Weyl, Methoden der organischen Chemie (Methods of OrganicChemistry), 4th Edition, Volume 8, page 139 (1952)).

Specific examples of starting compounds of the formula (II) which may bementioned are: the phenyl esters of methyl-carbamic acid and also of2-chloroethyl-, isopropyl-, tert.-butyl-, sec.-butyl-, iso-butyl-,tert.-pentyl, neo-pentyl-, 1,2,2-trimethylpropyl-,2,2,2-trifluoroethyl-, 2-ethoxyethyl-, 2-ethyl-mercaptoethyl-,ω-cyanohexyl-, allyl-, propargyl-, cyclopentyl-, cyclopropylmethyl-,cyclopentylmethyl-, cyclohexylmethyl-, (2,5-methano-cyclohexyl)-methyl-,cycloheptylmethyl-, cyclododecanylmethyl adamantylmethyl-,2-furylmethyl-, 2-pyranylmethyl-, 2-pyridylmethyl-, 3-pyridylmethyl-,4-pyridylmethyl-, 2-methylpentyl-, 2-ethylpentyl-, 2-methylhexyl-,2-ethylhexyl-, 2-methylcyclohexyl-, benzyl-, 4-chlorobenzyl-,4-nitrobenzyl-, phenethyl-, phenyl-, 4-chlorophenyl-,3,5-dichlorophenyl-, 3,4-dichlorophentyl-, 3-trifluoromethyl-,2-chloro-4-nitrophenyl-, 3-tolyl-, 4-ethylphenyl-, 3-anisidyl-,1-naphthyl-, 2-furyl-, 4-pyridyl- and 2-benzthiazolylcarbamic acid.

Preferred carbonic acid aryl ester halides of formula (II) to be used asstarting substances are those in which R³ independently of R² in thestarting substance of formula (II) represents a phenyl or naphthylradical which is optionally substituted by chlorine, methyl and/ormethoxy and X represents a chlorine or fluorine atom.

The carbonic acid aryl ester halides of the formula (III) used in theprocess of the present invention are known, or they can be prepared byknown processes. Thus, for example, the carbonic acid phenyl esterchlorides can be prepared in a manner which is in itself known, byphosgenation of phenols (see Houben-Weyl, Methoden der organischenChemie (Methods of Organic Chemistry), 4th Edition, Volume 8, page 103(1952)); the corresponding carbonic acid phenyl ester fluorides can beobtained analogously from phenols and difluorophosgene (see J. Cjem.Soc. [London] 1948, page 2183).

Specific examples of starting compounds of the formula (III) which maybe mentioned are: the carbonic acid ester chlorides of phenol,4-chlorophenol, 4-cresol and 1-naphthol and the carbonic acid esterfluoride of phenol.

The reaction according to the invention can be carried out in theabsence or in the presence of a diluent. If no diluent is used, it ismost appropriate to add the carbamic acid aryl ester of formula (II) inthe molten form to the carbonic acid aryl ester halide of formula (III),which is in the reaction vessel and has been warmed to the reactiontemperature. This embodiment is possible and particularly advantageousin those cases where the carbamic acid aryl ester of formula (II) to beemployed is completely stable at its melting point (see Example 5b).

Possible diluents for the carbonic acid aryl ester halide of formula(III), which is in general initially introduced, are high-boiling inertorganic solvents, such as chlorinated or nitrated aromatic hydrocarbons(for example chlorobenzene, the dichlorobenzenes, the trichlorobenzenesor nitrobenzene). Low-boiling inert organic solvents, such ashydrocarbons and chlorinated hydrocarbons (for example petroleum ether,cyclohexane, chloroform, difluorodichloromethane, or, preferably,methylene chloride) can appropriately be used as diluents for thecarbamic acid aryl ester of formula (II) to be added; these solventsevaporate at the reaction temperature and thereby simultaneously serveas "entraining agents" for removing the hydrogen halide formed. It isalso possible, and in many cases particularly advantageous, to carry outthe reaction in an excess of the carbonic acid aryl ester halide offormula (III) as used as a reactant.

The process according to the invention is carried out without theaddition of an acid-binding agent. However, it has proved advantageousfor the hydrogen halide formed in the course of the reaction to beremoved rapidly from the reaction mixture. This is most appropriatelyachieved by passing a continuous stream of air or nitrogen through thereaction mixture if the reaction is carried out in a high-boiling inertorganic solvent or in excess carbonic acid aryl ester halide of formula(III) as the diluent. In contrast, it is not necessary additionally topass a stream of air or nitrogen through the reaction mixture if alow-boiling solvent which, as mentioned above, functions as an"entraining agent" for removal of the hydrogen halide formed, is used.

The reaction temperatures can be varied within a substantial range. Thereaction is in general carried out, as indicated above, between 100° and300° C., preferably between 170° and 250° C.

If the reaction according to the invention is carried out in thepresence of an inert organic solvent as the diluent, in general 1 to 15moles, preferably 4 to 12 moles, of a carbonic acid aryl ester halide ofthe formula (III) are employed per mole of a carbamic acid aryl ester ofthe formula (II). In contrast, if an excess of carbonic acid aryl esterhalide of formula (III) is used as the diluent, generally up to 80moles, but appropriately about 5 to 40 moles and preferably about 10 to25 moles, of carbonic acid aryl ester halide of formula (III) can beemployed per mole of carbamic acid aryl ester of formula (II). It isthus advisable for the carbonic acid aryl ester halide of formula (III)in all cases to be employed in amounts which are greater than thestoichiometric amount.

The reaction products are isolated in a simple manner by separating thereaction mixture by distillation. Solid, higher-meltingimido-dicarboxylic acid diaryl esters can also be easily purified byrecrystallization.

The novel N-substituted imido-dicarboxylic acid diaryl esters accordingto the present invention can be used as intermediate products for thepreparation of known herbicidal active compounds from the1,3,5-triazine,2,4-(1H,3H)-dione series (see, for example, DE-OS (GermanPublished Specification) No. 2,254,200 and U.S. Pat. No. 4,056,527).

According to a process which has not hitherto belonged to the state ofthe art (and which is the subject of a separate application forprotection), 1,3,5-triazine-2,4-(1H,3H)-diones of the general formula##STR4## in which R¹ has the abovementioned meaning and

R⁴, R⁵ and R⁶ in each case represent identical

or different alkyl radicals, can be prepared with a high yield andpurity when the N-substituted imido-dicarboxylic acid diaryl estersaccording to the invention, of the general formula ##STR5## in which R¹,R² and R³ have the abovementioned meaning, are reaction with anisothiosemicarbazone of the general formula ##STR6## in which R⁴, R⁵ andR⁶ have the abovementioned meaning, in approximately stoichiometricamounts, without using a diluent and without adding a base as anauxiliary, at temperatures between 50° and 150° C., preferably between70° and 120° C.

The triazinediones of formula (IV) can be worked up and isolated, forexample, by a procedure in which the (optionally substituted) phenol orphenol mixture formed in the condensation reaction--(I)+(V)→(IV)--isdistilled off in vacuo and the residue is purified, if necessary, bydistillation under a high vacuum or by recrystallization.

The 1,3,5-triazine-2,4(1H,3H)-diones of formula (IV) thus prepared arethemselves herbicidal active compounds; however, they can also be easilyconverted into the corresponding1-amino-1,3,5-triazine-2,4(1H,3H)-diones of the general formula ##STR7##in which R¹ and R⁶ have the abovementioned meaning, which are likewiseexcellent herbicides, by hydrolytic splitting off of the alkylideneradical (═CR⁴ R⁵) which serves as a protective group. Furthermore, theS-alkyl radicals (--SR⁶) in formulae (IV) and (VI) can be replaced byalkylamino or dialkylamino groups by reaction with primary or secondaryamines, herbicidal active compounds which are also known being obtained(see likewise DE-OS (German Published Specification) No. 2,254,200 andU.S. Pat. No. 4,056,527).

The new process given here for the preparation of the herbicidal activecompounds of the general formulae (IV) and (VI) and 6-amino-derivativesthereof, in which the imido-dicarboxylic acid diaryl esters of formula(I) according to the invention are used as starting compounds, hasconsiderable and surprising advantages compared with the processesalready known, for example DE-OS (German Published Specification) No.2,254,200. Thus, the cyclization reaction can be carried out in the meltof the starting materials without using solvents. No other auxiliaries,such as, for example, organic bases, are required in this procedure. Theonly by-products are phenols (no hydrogen halides!), which can easily beseparated off and re-used. Finally, the imidodicarboxylic acid diarylesters of formula (I) employed as starting substances can be prepared inhigh yields in an industrially simple manner from readily accessibleprecursors by the process claimed in the present application.

The isothiosemicarbazones of the general formula (V) are known or theycan be prepared by known processes, for example by S-alkylation ofthiosemicarbazones (see Houben-Weyl, Methoden der organischen Chemis(Methods of Organic Chemistry), 4th Edition, Volume 9, page 912).

The synthesis of the particularly effective herbicidal active compound1-amino-6-ethylthio-3-neopentyl-1,3,5-triazine-2,4(1H,3H)-dione (thecompound of formula (VIa)) (see, for example Danish Patent SpecificationNo. 136,067), starting from the compound N-neopentylimido-dicarboxylicacid diphenyl ester of formula (Ia) according to the invention, isdescribed below by way of example; the course of the reaction can berepresented by the following equation: ##STR8##

A mixture of 65.4 g (0.2 mole) of N-neopentylimido-dicarboxylic aciddiphenyl ester (see Preparation Example 5) and 31.8 g (0.2 mole) ofacetone S-ethylisothiosemicarbazone (the compound of formula (Va)) wasmelted under nitrogen and the melt was stirred at 100° C. for 5 hours.The phenyl formed was then distilled off in vacuo. The residue, whichessentially consisted of1-isopropylideneamino-6-ethylthio-3-neopentyl-1,3,5-triazine-2,4(1H,3H)-dione(the compound of formula (IVa)), was dissolved in 200 ml of isopropanol.To split off the isopropylidene protective group hydrolytically, 2.8 gof p-toluenesulphonic acid were added, and 14.4 ml of water were addeddropwise at a temperature of 60° C. and under a pressure of 200 to 300mbar in the course of half an hour. The acetone formed was distilled offduring the reaction, together with about 100 ml of isopropanol. The1-amino-6-ethylthio-3-neopentyl-1,3,5-triazine-2,4(1H,3H)-dione (thecompound of formula (VIa)) which had crystallized out was filtered offat 0° C. and washed with methanol. 38.2 g of (the compound of formula(VIa)) of melting point 202° C. were obtained, corresponding to a yieldof 74% of theory.

Herbicidally active1-amino-3-isobutyl-6-methylthio-1,3,5-triazine-2,4(1H,3H)-dione (thecompound of formula (VIb)), which is known (see, for example, DanishPatent Specification No. 136,067) could be prepared in an analogousmanner starting from the compound N-isobutylimido-dicarboxylic aciddiphenyl ester (the compound of formula (Ib)) according to theinvention, it being possible for the intermediate product1-isopropylideneamino-3-isobutyl-6-methylthio-1,3,5-triazine,2-4(1H,3H)-dione(the compound of formula (IVb)) to be isolated. ##STR9##

34.6 g (0.11 mole) of N-isobutyl-imido-dicarboxylic acid diphenyl ester(the compound of formula (Ib)) (see Preparative Example 3) and 16.0 g(0.11 mole) of acetone S-methyl-isothiosemicarbazone were melting at 50°C. and the melt was stirred for 4 hours in an oil bath of 100° C. Thephenol formed was distilled off under a pressure of 18 mbars, the bathtemperature being increases to 140° C. The residue (30.3 g) solidified;it was boiled up with 150 ml of cyclohexane, 22.4 g of pure1-isopropylideneamino-3-isobutyl-6-methylthio-1,3,5-triazine-2,4(1H,3H)-dione(the compound of formula (IVb)) of melting point 125° to 127° C.remaining as undissolved material. A further 6.4 g of the compound offormula (IVb) crystallized from the filtrate of the mixture. The totalyield was 28.8 g (97% of theory). The compound of formula (IVb) could bedistilled: boiling point: 165° C. under 0.38 mbar. ##STR10##

27.0 g (0.1 mole) of the compound of formula (IVb) were dissolved in 200ml of isopropanol at 60° C. in a distillation apparatus and a pressureof 260 to 200 mbars was established, so that the solvent started to boiland was condensed in the descending condenser. The internal temperaturewas 45° to 50° C. A solution of 0.4 ml of concentrated sulphuric acid in7 ml of water was then added dropwise in the course of 15 minutes, about70 ml of isopropanol, together with the acetone formed, being distilledoff during this period. 14.5 g of1-amino-3-isobutyl-6-methylthio-1,3,5-triazine-2,4(1H,3H)-dione (thecompound of formula (VIb)) of melting point 167° to 169° C. crystallizedout, at 0° C., from the solution which remained; a further 4.5 g wereobtained from the concentrated filtrate of the mixture. The total yieldof 19.0 g corresponding to 83% of theory.

The Preparative Examples which follow are illustrated processes for theproduction of compounds of the invention in more detail.

Example 1 (CH₃)₂ CH--N(CO--O--C₆ H₅)₂

600 ml (4.72 moles) of carbonic acid phenyl ester chloride were broughtto the boil in a 4-necked flask provided with a stirrer, gas inlet tube,reflux condenser and dropping funnel while passing through a stream ofair or nitrogen. A solution of 71.6 g (0.4 mole) of isopropyl-carbamicacid phenyl ester (melting point: 78° to 80° C.) in 300 ml of carbonicacid phenyl ester chloride (2.36 moles) was then uniformly addeddropwise at an internal temperature of 180° to 185° C. in the course of5 hours, during which air or nitrogen was further passed through thereaction solution for rapid removal of the hydrogen chloride formed. Themixture was subsequently stirred for a further 2 hours at the boilingpoint, the excess carbonic acid phenyl ester chloride was distilled offat a bath temperature of 140° C. and under a pressure of 20 mbars andthe residue was distilled in vacuo.

57.9 g of N-isopropyl-imido-dicarboxylic acid diphenyl ester with aboiling point of 155° C./0.07 mbar and a melting point of 35° to 37° C.were obtained. The purity, determined by gas chromatography, was 98%;this corresponded to a yield of 47% of theory.

Example 2 (CH₃)₃ C--N(CO--O--C₆ H₅)₂

77.2 g (0.4 mole) of tert.-butyl-carbamic acid phenyl ester (meltingpoint: 92° C.) were reacted with excess carbonic acid phenyl esterchloride (4.72 moles) as descrined in Example 1 and, after working up,26.4 g of N-tert.-butyl-imido-dicarboxylic acid diphenyl ester with aboiling point of 150° C./0.1 mbar and a melting point of 132° C. (fromethyl acetate) were obtained.

The purity, determined by gas chromatography, was 99.7%; thiscorresponded to a yield of 21% theory.

Example 3 (CH₃)₂ CH--CH₂ --N(CO--O--C₆ H₅)₂

77.2 g (0.4 mole) of isobutyl-carbamic acid phenyl ester (melting point:67° C.) were reacted with excess carbonic acid phenyl ester chloride(4.72 moles) analogously to Example 1. After the distillation, 102.4 gof N-isobutyl-imido-dicarboxylic acid diphenyl ester with a boilingpoint of 160° C./0.1 mbar and a purity of 93.7% were obtained. Afterrecrystallizing from about 500 ml of petroleum ether, filtering off thecrystals at -70° C. and washing them with intensely cooled petroleumether, 88 g of the given compound with a melting point of 40° C. and apurity of 100%, corresponding to 70% of theory, were obtained.

Example 4 ##STR11##

77.2 g (0.4 mole) of sec.-butyl-carbamic acid phenyl ester (meltingpoint: 43° C.) were reacted with excess carbonic acid phenyl esterchloride (4.72 moles) analogously to Example 1. After working up, 45.8 gof N-sec.-butyl-imido-dicarboxylic acid diphenyl ester with a boilingpoint of 165°-170° C./0.2 mbar and a refractive index n_(D) ²⁰ of 1.5336were obtained. The purity, determined by gas chromatography, was 97.8%,corresponding to a yield of 36% of theory.

Example 5a (CH₃)₃ C--CH₂ --N(CO--O--C₆ H₅)₂

A solution of 331 g (1.6 moles) of neopentylcarbamic acid phenyl esterin 1,000 g (6.39 moles) of carbonic acid phenyl ester chloride was addeddropwise to 4,000 g (25.56 moles) of boiling carbonic acid phenyl esterchloride, through which a vigorous stream of nitrogen was passed, in thecourse of 5 hours. The overhead temperature in the reflux condenser waskept at 80° to 90° C., so that the small amount of neopentyl isocyanateformed as the by-product could be distilled off over the top with thestream of nitrogen and condensed in a subsequent descending condenser.(After reaction with phenol to give neopentyl-carbamic acid phenylester, it was then passed again to the reaction). The mixture wassubsequently stirred for 4 hours, while passing further nitrogenthrough, the excess carbonic acid phenyl ester chloride was thendistilled off at a bath temperature of 140° C. and under a pressure of20 mbars and the residue was distilled from a heating bath of 170° C.until a boiling point of 150° C. under a pressure of 0.6 mbar wasreached. The residue consisted of 96.5% pureN-neopentyl-imido-dicarboxylic acid diphenyl ester. Yield: 489 g (90% oftheory). A sample recrystallized from petroleum ether melted at 81° C.The substance could be distilled: boiling point: 156° C./0.02 mbar.

The neopentyl-carbamic acid phenyl ester which was used as the startingmaterial and is novel, could be prepared, for example as follows,starting from neopentylamine:

A solution of 80 g (2 moles) of sodium hydroxide and 176 g (2 moles) of90% pure neopentylamine in 3.4 liters of water was added dropwise to asolution of 329 g (2.1 moles) of carbonic acid phenyl ester chloride in1 liter of toluene, while stirring vigorously. An internal temperatureof 10° to 20° C. was maintained by cooling. When the reaction had ended,the phases were separated, the organic phase was washed with water andfiltered and the filtrate was evaporated to dryness. 408 g of a 97% purecrude product (95.6% of theory) which had a melting point of 69° to 72°C. and was sufficiently pure for further reactions were obtained. Afterrecrystallizing from 2 liters of petroleum ether, 365 g, of meltingpoint 77° to 78° C., were obtained.

Example 5b (CH₃)₃ C--CH₂ --N(CO--O--C₆ H₅)₂

variant of the process of Example 5a

414 g (2 moles) of neopentyl-carbamic acid phenyl ester were uniformlyadded dropwise as a melt, from a dropping funnel heated to 120° C., to2.54 liters (20 moles) of boiling carbonic acid phenyl ester chloride inthe course of 8 hours, while passing through a vigorous stream ofnitrogen. The mixture was worked up analogously to Example 5a and 510 gof 98% pure N-neopentylimido-dicarboxylic acid diphenyl ester wereobtained. A further 37 g of the same product could be obtained byworking up the portion which distilled between 120° and 150° C. under0.6 mbar.

The total yield was 82% of theory of N-neopentylimido-dicarboxylic aciddiphenyl ester.

The neopentyl-carbamic acid phenyl ester used as the starting materialwas prepared by another process as follows:

2,140 g (10 moles) of carbonic acid diphenyl ester were melted at 80° C.870 g (10 moles) of neopentylamine were added dropwise at thistemperature in the course of 3 hours, the phenol formed was distilledoff in vacuo and the residue was recrystallized from petroleum ether.1,725 g (83% of theory) of neopentyl-carbamic acid phenyl ester ofmelting point 77° to 78° C. were obtained.

Example 5c (CH₃)₃ C--CH₂ --N(CO--O--C₆ H₅)₂

variant of the process of Examples 5a and 5b

A 4 liter three-necked flask was provided with a stirrer and refluxcondenser. A Reitmeir attachment connected to a descending distillationbridge with an intensive condenser was fitted to the reflux condenser. Aspecial gas inlet frit, to which a dropped funnel was attached via aground glass joint was immersed in the stirred flask. The gas inlet tubeof the frit was connected to the dropping funnel for pressurecompensation. The reflux condenser was charged with water of 80° to 95°C. and the descending condenser was charged with cold water.

2.54 liters (20 moles) of carbonic acid phenyl ester chloride were thenheated to the boiling point in the stirred flask. A solution of 414 g (2moles) of neopentyl-carbamic acid phenyl ester in 300 ml of methylenechloride were then uniformly added dropwise into the gas inlet frit at abottom temperature of 185° to 190° C. in the course of 9 hours, thehydrogen chloride formed being immediately removed from the reactionmedium by the evaporating solvent. The solvent was condensed in theintensive condenser and the hydrogen chloride entrained was absorbed inwater in a downstream wash tower. The boiling carbonic acid phenyl esterchloride was in this manner condensed in the reflux condenser and wasprevented from being entrained with the methylene chloride vapor by theReitmeir attachment.

The mixture was worked up analogously to Example 5a and a total of 581 gof 98% pure N-neopentyl-imido-dicarboxylic acid diphenyl ester,corresponding to a yield of 87% of theory, was obtained.

Example 6 ##STR12##

A solution of 87.6 g (0.4 mole) of cyclohexylcarbamic acid phenyl ester(melting point: 136° to 137° C.) in 1,000 g (6.4 moles) of carbonic acidphenyl ester chloride was added dropwise to 750 g (4.8 moles) of boilingcarbonic acid phenyl ester chloride and the mixture was boiled underreflux for a further 3 hours, while passing nitrogen through, and wasworked up analogously to Example 1.

83.1 g of N-cyclohexyl-imido-dicarboxylic acid diphenyl ester with aboiling range of 165° to 175° C. under 0.1 mbar and a purity, determinedby gas chromatography, of 97.5% were obtained. A sample recrystallizedfrom petroleum ether melted at 85° C. Yield: 60% of theory.

Example 7 ##STR13##

83.0 g (0.4 mole) of cyclopentylcarbamic acid phenyl ester (meltingpoint: 115°-117° C.) were reacted with excess carbonic acid phenyl esterchloride (a total of 8.8 moles) analogously to Example 6. 81.2 g ofN-cyclopentyl-imido-dicarboxylic acid diphenyl ester with a boilingrange of 155° to 182° C. under 0.1 mbar and a purity, determined by gaschromatography, of 86.8%, corresponding to a yield of 54.2% of theory,were obtained. After recrystallizing from 300 ml of petroleum ether, 52g of melting point 53° C. were obtained.

Example 8 ##STR14##

A solution of 56.4 g (0.2 mole) of 3,5-dichlorophenyl-carbamic acidphenyl ester (melting point: 141° C.) in 1,015 ml (8.0 moles) ofcarbonic acid phenyl ester chloride were added dropwise to 306 ml (2.4moles) of boiling carbonic acid phenyl ester chloride in the course of 5hours. During this addition, nitrogen was passed through the reactionsolution. The mixture was then boiled under reflux for a further 4 hoursand the excess carbonic acid phenyl ester chloride was distilled off ata bath temperature of 140° C. and under a pressure of 20 mbars. Theresidue contained 3,5-dichlorophenyl isocyanate and diphenyl carbonateas impurities.

These impurities were largely distilled off at a bath temperature of150° C. and under a pressure of 0.3 mbar. The distillation residue wasrecrystallized from 300 ml of ethyl acetate. 15.6 g (19.4% of theory) ofN-(3,5-dichlorophenyl)-imido-dicarboxylic acid diphenyl ester of meltingpoint 178° to 180° C. were obtained.

Example 9 (C₂ H₅)₂ CH--N(CO--O--C₆ H₅)₂

A solution of 82.8 g (0.4 mole) of (1-ethyl-propyl)carbamic acid phenylester (melting point: 65° to 67° C.) in 500 ml (3.9 moles) of carbonicacid phenyl ester chloride was added dropwise to 600 ml (4.7 moles) ofboiling carbonic acid phenyl ester chloride in the course of 5 hours, avigorous stream of nitrogen being passed through the boiling solutionduring this addition. The mixture was boiled under reflux for a further4 hours, the excess carbonic acid phenyl ester chloride was distilledoff in vacuo and the reaction was distilled under a high vacuum.

84.6 g (64.7%) of N-(1-ethyl-propyl)-imidodicarboxylic acid diphenylester with a boiling point of 134° C./0.09 mbar and a melting point of54° to 56° C. (from pentene) were obtained.

Example 10 ##STR15##

A solution of 59.1 g (0.23 mole) of neopentylcarbamic acid α-naphthylester (melting point: 116° to 117° C.) in 600 ml (4.7 moles) of carbonicacid phenyl ester chloride were added dropwise to 300 ml (2.35 moles) ofboiling carbonic acid phenyl ester chloride in the course of 5 hours,during which, a vigorous stream of nitrogen was passed through thesolution. After distilling off the excess carbonic acid phenyl esterchloride, the residue which remained (83.0 g, 95.4% pure according tothe gas chromatogram--corresponding to a yield of 91.3%) was distilledunder a high vacuum.

52.7 g of N-neopentyl-imido-dicarboxylic acid phenyl α-naphthyl ester ofboiling point 230° to 235° C./0.25 mbar were obtained.

Example 11 ##STR16##

A solution of 29.4 g (0.114 mole) of neopentylcarbamic acid α-naphthylester (melting point: 117° to 118° C.) in 510 g (2.47 moles) of carbonicacid α-naphthyl ester chloride were added dropwise to 250 g (1.21 moles)of carbonic acid α-naphthyl ester chloride, heated to 230° to 240° C.,in the course of 5 hours, during which a vigorous stream of air waspassed through the solution. The mixture was stirred at 240° C. for afurther 4 hours, whilst passing further air through, the excess carbonicacid α-naphthyl ester was distilled off (boiling point: 155° C. under 20mbars) and the traces still present were then removed by heating theresidue to 140° C. under 0.03 mbar.

The residue (49 g) was recrystallized twice from in each case 500 ml ofpetroleum ether.

22.9 g (47%) of N-neopentyl-imido-dicarboxylic acid di-α-naphthyl esterof melting point 92°-93° C. were obtained.

Example 12 CF₃ --CH₂ --N(CO--O--C₆ H₅)₂

21.9 g (0.1 mole) of 2,2,2-trifluoroethylcarbamic acid phenyl ester(melting point: 88° to 90° C.) are introduced into 85 ml (0.67 mole) ofcarbonic acid phenyl ester chloride and the mixture was heated underreflux for 20 hours. After distilling off the excess carbonic acidphenyl ester chloride, the residue was subjected to incipientdistillation over a short Vigreux column until the boiling point reaches132° C. under 0.1 mbar. 28.7 g of crude product which, according to thegas chromatogram, consisted of 98% pureN-(2,2,2-trifluoroethyl)-imido-dicarboxylic acid diphenyl ester(corresponding to a yield of 83% of theory) were obtained as theresidue. A sample recrystallized from wash benzine melted at 76° C. Theboiling point was 140° C. under 0.3 mbar.

It will be understood that the specification and examples areillustrative but not limitative of the present invention and that otherembodiments within the spirit and scope of the invention will suggestthemselves to those skilled in the art.

What is claimed is:
 1. Process for the production of N-substitutedimido-dicarboxylic acid diaryl ester compound of the formula ##STR17##which comprises reacting a carbamic acid aryl ester of the formula:

    R.sup.1 --NH--CO--OR.sup.2                                 (II)

with a carbonic acid aryl ester halide of the formula

    X--CO--OR.sup.3                                            (III)

wherein R¹ is an optionally substituted aliphatic, cycloaliphatic,araliphatic, aromatic or heterocyclic radical; and R² and R³ can beidentical or different and represent an optionally substituted arylradical; and X is a halogen; in the absence of an acid-binding agent, attemperatures ranging from about 170° C. to about 250° C.
 2. Process ofclaim 1 wherein R¹ is straight or branched alkyl of 1 to 10 carbonatoms.
 3. Process of claim 1 wherein R¹ is substituted alkyl of 1 to 10carbon atoms wherein the substituents are selected from lower alkoxy,lower alkylmercapto, halogen, cyano or nitro.
 4. Process of claim 1wherein R¹ is alkenyl of 3 to 8 carbon atoms.
 5. Process of claim 1wherein R¹ is alkynyl of 3 to 8 carbon atoms.
 6. Process of claim 1wherein R¹ is a cycloaliphatic radical of 5 to 8 carbon atoms. 7.Process of claim 1 wherein R¹ is a lower alkyl substitutedcycloaliphatic radical of 5 to 8 carbon atoms.
 8. Process of claim 1wherein R¹ is an araliphatic radical of 7 to 12 carbon atoms.
 9. Processof claim 1 wherein R¹ is a substituted araliphatic radical of 7 to 12carbon atoms wherein the aromatic ring system is substituted by at leastone of halogen, nitro, trifluoromethyl, cyano, lower alkyl and loweralkoxy.
 10. Process of claim 1 wherein R¹ is an aromatic radical of from6 to 12 carbon atoms.
 11. Process of claim 1 wherein R¹ is a substitutedaromatic radical of from 6 to 12 carbon atoms wherein the substituentsare selected from halogen, nitro, trifluoromethyl, cyano, lower alkyland lower alkoxy.
 12. Process as claimed in claim 1 wherein the reactionis carried out in the presence of a diluent.
 13. Process as claimed inclaim 1 whereinR¹ is a straight-chain or branched alkyl radical whichhas 1 to 10 carbon atoms and is optionally substituted by lower alkoxy,lower alkylmercapto, halogen, cyano or nitro; an alkenyl radical with 3to 8 carbon atoms; an alkynyl radical with 3 to 8 carbon atoms; acycloaliphatic radical which has 5 to 8 carbon atoms and is optionallysubstituted by lower alkyl; an araliphatic radical with 7 to 12 carbonatoms, the aromatic ring system being optionally substituted by halogen,nitro, trifluoromethyl, cyano, lower alkyl and/or lower alkoxy; anaromatic radical which has 6 to 12 carbon atoms and is optionallysubstituted by halogen, nitro, trifluoromethyl, cyano, lower alkyland/or lower alkoxy; or a heterocyclic radical with 5 or 6 ring atomsand 1 to 3 hetero ring atoms; and R² and R³ independently represent aphenyl or naphthyl radical which is optionally substituted by chlorine,methyl and/or methoxy.